Mid-length golf putter

ABSTRACT

A dip-molded grip for a mid-length golf putter is preferably made of plastisol, has a circular cross-section, and a length of about 19 inches. The grip is made by dipping a mold rod into two types of plastisol and baking the plastisol layers. The result is a grip that fits any individual and provides an ideal surface.

[0001] This application claims priority from U.S. Provisional Application No. 60/316,146 filed Aug. 30, 2001 for GOLF PUTTER GRIP.

BACKGROUND OF THE INVENTION

[0002] The present invention relates generally to a golf club grip. In particular, the present invention relates to a one-piece grip for a mid-length putter.

[0003] A popular trend in the golf industry is the mid-length putter. This design is different from conventional putters that typically vary in length from 33 to 35 inches and long putters which vary in length from 46 to 55 or more inches. The key advantage of the mid-length putter is that the player's mid-section becomes a pivot point for the butt end of the putter grip during the stroke. It increases stability and improves accuracy for most players. Indeed, top PGA pros have experienced an evolution in their putting skill. Vijay Singh, for example, went from a 99 putting rank in 2000 to near the top in 2001. In 1999, Paul Azinger's putting ranking was 141st and improved to 4th in 2000.

[0004] Every putter model consists of three main components—the putter head, the shaft, and the grip. Ordinarily, the grip is less significant in terms of function, and cosmetics have been the main concern of players and manufacturers alike. Putter grips are basically the same. They measure about one foot in length and have a 0.75 inch diameter.

[0005] The “split” grip concept originated for the long putters, which were introduced more then a decade ago and have seen a resurgence in popularity recently. The split grip allows players to separate their hands to control these extra long designs.

[0006] This leaves the mid-length putter lacking for an ideal grip, and most custom club makers must modify grips intended for the long putter. For example, some shops use just the upper grip of two-piece models.

[0007] A two-piece grip may be appropriate for the long putter, but it has limited application for the mid-length putter. First, there is considerable variation in body size and shape (under 5 feet tall to over 6 feet tall; slim waists and not-so-slim waists) among golfers with each having a different gripping style (placing hands high on the grip or bending over and placing hands low on the grip). A two-piece grip forces players to adapt to the grip rather than giving players the freedom to experiment with what works best for them. Second, grips intended for the long putter are generally too heavy and inappropriate in diameter. To make matters worse, the material is too dense and this hampers putter head “feel,” which is essentially the ability of the player to sense how the putter head is reacting during the stroke. Feel is an important consideration among professional and amateur golfers when considering model choice and purchase.

[0008] Grip weight is critical because of its interrelationship with the shaft and the putter head. If the grip is too heavy, heavier putter heads are necessary for the player to “feel” the stroke and accurately judge feedback when striking the ball. Today's players are accustomed to a certain look and do not want to adapt to an entirely new one unless it is both pleasing and functional. Furthermore, keeping the putter head size to current compact dimensions improves precision. A few “oversize” putter heads have enjoyed limited success in the marketplace, but the acknowledged common ground is approximately 4-5 inches long and 1-2 inches wide. Forcing players to adapt to a larger putter face is a significant marketing disadvantage. Again, a grip that is too heavy causes the putter head to feel too light.

[0009] Grip density can have a big impact on putter head “feel.” A common material used for conventional putter grips is synthetic rubber, and the common manufacturing process is injection molding. This combination is too dense when used at the length and width required for a mid-length putter.

[0010] Additionally, tactile sense is ignored by manufacturers. It is assumed that either the player does not care or surface material does not matter. This is an unwarranted assumption when it comes to the mid-length putter, because the player must avoid slippage during the putting stroke. Since the main tenant of the body pivot system used with a mid-length putter is an anchored grip against the mid-section, a grip that slips alters the pivot point and this affects accuracy.

[0011] As alluded to above, another key aspect of grip design is the ability to modify weight. It takes at least ten shaft lengths to fit the golfing public to a personal mid-length design, and putter head feel can change drastically with different lengths. For example, assuming putter head weight remains constant, shorter length putters make the head feel lighter while longer lengths make it feel heavier. Once the ideal putter head feel is achieved, reproducing it for all lengths either requires varying putter head weight (an inventory nightmare) or varying grip weight.

[0012] Finally, tooling costs associated with the manufacturing process is expensive for injection molding, the most common method of forming grips. A mold for injection molding can typically cost as much as $30,000.00. In addition, injection molding requires tedious paint-filling to add customized logos.

BRIEF SUMMARY OF THE INVENTION

[0013] The present invention is a grip for a golf putter, and a method for making the grip. The grip has a circular cross-section and a length greater than about 11 inches. The method of making the grip is a dip-molded process where a first flexible layer is formed on a mold rod followed by a second flexible layer. The first and second layers coated on the mold rod are baked to cure the layers. The process results in an ideal grip for putters.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1A is a side view of a player using a putter of the present invention.

[0015]FIG. 1B is a front view of a player's midsection showing placement of a putter of the present invention.

[0016]FIG. 2A is a front view of the grip on a putter.

[0017]FIG. 2B is a cross section of the closed end of the grip on a putter.

[0018]FIG. 3 is an illustration of preheating a mold rod tool in an oven chamber.

[0019]FIG. 4 is an illustration of dipping mold rods into plastisol.

[0020]FIG. 5 is an illustration of mold rods coated with plastisol.

[0021]FIG. 6 is an illustration of dipping mold rods into foamable plastisol.

[0022]FIG. 7 is an illustration of mold rods coated with foamable plastisol.

[0023]FIG. 8 is an illustration of cured grips in an oven chamber.

[0024]FIG. 9 is an illustration of removing the grips from the mold rods.

[0025]FIG. 10 is an illustration of inserting a putter shaft into a grip.

DETAILED DESCRIPTION

[0026]FIG. 1A is a side view of a player using the present invention.

[0027] Putter 10 includes grip 12, shaft 14, and head 16. Shaft 14 of putter 10 is long enough to rest at the mid-section of the player.

[0028]FIG. 1B is a front view of the player's midsection while using a putter of the present invention. FIG. 1B shows grip 12 and shaft 14. Grip 12 is preferably about 19 inches long but can be any length greater than 11 inches when used with a mid-length putter. As shown in FIG. 1A and FIG. 1B, grip 12 is also preferably used on a mid-length putter that rests on the midsection of the player. Most preferably, putter 10 rests at about the naval of the player.

[0029]FIG. 2A is a front view of the upper end of putter 10. FIG. 2 shows putter 10 with grip 12 and shaft 14. Grip 12 further includes closed end 18 and open end 20.

[0030]FIG. 2B is a cross sectional view of closed end 18 of grip 12. FIG. 2B shows shaft 14 and grip 12 with plastisol layer 22 and foamed plastisol layer 24. Plastisol layer 22 is the first layer covering about a 0.5 inch length of shaft 14. Plastisol layer 22 is preferably between about 0.03 inch to about 0.06 inch thick and has a durometer hardness of about 70+/−2. The inside diameter is about 0.4 inch, and the outside diameter is between about 0.43 inch to about 0.46 inch. Plastisol layer 22 covers the whole end of shaft 14. The purpose of the relatively hard plastisol layer is to provide a more durable closed end 18 of grip 12. With use and abuse shaft 14 might otherwise break through grip 12.

[0031] Foamed plastisol layer 24 is the second layer preferably covering about 19 inches of shaft 14. Foamed plastisol layer 24 is preferably has a thickness of about 0.25 inch and a durometer hardness of about 20+/−5. The inside diameter at closed end 18 is between about 0.43 inch to about 0.46 inch, and the outside diameter is about 1.0 inch. The outside diameter may range from about 0.9 to about 1.1 inches for a customized fit for any player. Foamed plastisol 22 also provides an ideal grip surface for a mid-length putter. Grip 12 has a slightly sticky, and yet smooth and tactile surface that avoids slippage during the putting stroke. Additionally, the surface of grip 12 accomodates inexpensive silk-screening for customized logos.

[0032] Plastisol is a suspension resin of finely ground polyvinyl chloride (PVC) particles suspended in a plasticizer. Examples of plasticizers that may be used, but not limited to, include dibutyl maleate, dibutyl phthal ate, dibutyl sebacate, di ethyl phthalate, di-isobutyl phthalate, di-isodecyl phthal ate, id-isononyl phthalate, dimethyl phthalate, dioctyl adipate, dioctyl azelate, dioctyl phthalate, dioctyl sebacate, and trioctyl trimellitate. Heat fuses the PVC particles into a copolymer commonly called “vinyl.”

[0033] Foamed plastisol is plastisol with an added foaming agent or blowing agent. An ideal foaming or blowing agent evaporates quickly at about the same temperature that the PVC particles fuse. The gas formed by evaporation of the blowing agent creates bubbles in the plastisol, which give foamed plastisol its airiness.

[0034]FIG. 3 illustrates preheating mold rod tool 26. FIG. 3 shows mold rod tool 26 with mold rods 28 and oven chamber 30. Mold rod tool 26 is the only major tooling investment required for the process of the present invention. In the first step, mold rod tool 26 is preheated at about 415° F. for about 12 minutes in oven chamber 30. Each mold rod 28 must be heated such that when it is exposed to the plastisol, the plastisol will begin to polymerize and coat mold rods 28.

[0035]FIG. 4 illustrates dipping mold rods 28 into plastisol 34. FIG. 4 includes mold rod tool 26 with mold rods 28 and vat 32 with plastisol 34. Mold rods 28 are suspended and lowered into vat 32 containing plastisol 34, which has a durometer hardness rating of 70+/−2. Mold rods 28 are dipped in about 0.5 inch for a dwell-time of approximately 10 to 15 seconds. The dwell-time is important, because it determines the thickness of the coating on mold rods 28. If a thicker coating of plastisol is desired, mold rod 18 has a longer dwell-time. If a thinner layer of plastisol is desired, the dwell-time of mold rod 18 is shorter.

[0036]FIG. 5 illustrates plastisol 34 coated on mold rods 28. FIG. 5 includes the identical structures to FIG. 4. Mold rods 28 are shown with an approximately 0.5 inch long coating of plastisol 34. With a dwell-time of about 10 seconds to 15 seconds, plastisol 34 is approximately 0.03 inch to 0.06 inch thick. Since there is no foaming agent nor blowing agent, the thickness of plastisol 34 remains the same even after curing.

[0037]FIG. 6 illustrates dipping mold rods 28 into foamable plastisol 36. FIG. 6 includes mold rod tool 26 with mold rods 28 and vat 32 with foamable plastisol 36. In the next step, mold rods 28, while being suspended, are lowered into vat 32 containing foamable plastisol 36, which is a mixture of plastisol having a durometer hardness rating of 20+/−5 and a foaming agent or a blowing agent. Mold rods 28 are dipped into foamable plastisol 36 about 19 inches for a dwell-time of 2.5 minutes. Again, the dwell-time determines the thickness of the coating on mold rod 18.

[0038]FIG. 7 shows mold rods 28 coated with foamable plastisol 36. FIG. 7 includes identical structures to FIG. 6. At this point, the thickness of foamable plastisol 36 is preferably about 0.15 inch. This, however, is the thickness before curing.

[0039]FIG. 8 illustrates cured grips 12 in oven chamber 30. FIG. 8 shows mold rod tool 26 with mold rods 28, foamed plastisol 38, and oven chamber 30. Mold rods 28 coated with plastisol 34 and foamable plastisol 36 are cured by baking in oven chamber 30 at about 415° F. for about 9 to 10 minutes. Baking completes polymerization of the plastisol and activates the foaming agent or blowing agent in foamable plastisol 36 to form foamed plastisol 38 shown on mold rods 28. The thickness of foamed plastisol 38 is approximately 0.25 inch. Foamed plastisol 38 is flexible and slightly elastic. About 1% shrinkage may occur during the curing step. Preferably, grip 12 has a mass between about 145-165 grams.

[0040]FIG. 9 illustrates removing grip 12 from mold rod 28. FIG. 9 includes mold rod tool 26 with mold rod 28, grip 12 with closed end 18 and open end 20, and air hose 40. Once removed from oven chamber 30 and cooled, grip 12 is removed from mold rod 28 using air pressure. Air hose 40 blows air into open end 20 of grip 12, which allows it to slip off of mold rod 28.

[0041]FIG. 10 illustrates applying grip 12 over shaft 14 of a putter. FIG. 10 includes grip 12 with closed end 18 and open end 20, shaft 14, and air hose 40. To slip grip 12 over shaft 14, a small opening is created at closed end 18 of grip 12, and air hose 40 blows air into grip 12 allowing it to easily slip over shaft 14 of putter 10. Alternatively, grip 12 can be slipped over shaft 14 without using air pressure.

[0042] The process of the present invention provides an easy way to vary the volumes and diameters of grip 12 by varying the dwell-time in foamable plastisol 36. Foamed plastisol 38 is lighter and airier so that even large diameter grips do not become too heavy for a mid-length putter. A club builder can easily pair lighter grips to shorter putters and heavier grips to longer putters.

[0043] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. 

1. A grip for a golf putter, the grip comprising: a dip-molded tube having a circular cross section, a length greater than about 11 inches, and an inside diameter that accommodates a golf putter shaft.
 2. The grip of claim 1 wherein the grip has a length of about 19 inches.
 3. The grip of claim 1 wherein the dip molded grip further comprises: a first layer having a first durometer hardness rating; and a second layer having a second durometer hardness rating that is less than the first durometer hardness rating of the first layer.
 4. The grip of claim 3 wherein the first layer is between about 0.03 inch and about 0.06 inch thick.
 5. The grip of claim 3 wherein the second layer is about 0.25 inch thick.
 6. The grip of claim 3 wherein the first layer and the second layer are plastisol.
 7. The grip of claim 6 wherein the second layer is foamed plastisol.
 8. The grip of claim 3 wherein the first layer has a durometer hardness of about 68 to about 72 and the second layer has a durometer hardness of about 15 to about
 25. 9. The grip of claim 3 wherein the first layer has a durometer hardness of about 70 and the second layer has a durometer hardness of about
 20. 10. The grip of claim 3 wherein the first layer is about 0.5 inch long.
 11. The grip of claim 1 having a diameter between about 0.9 inch and about 1.1 inch.
 12. The grip of claim 1 having a diameter of approximately 1.0 inch.
 13. The grip of claim 1 wherein the grip has a mass between about 145-165 grams.
 14. A golf club comprising: a shaft; a head mounted on a lower end of the shaft; and a plastisol grip mounted on an upper end of the shaft and having a length greater than about 11 inches.
 15. The golf club of claim 14 wherein the plastisol grip is about 19 inches.
 16. The golf club of claim 14 wherein the plastisol layer further comprises: a plastisol layer; and a foamed plastisol layer.
 17. The golf club of claim 16 wherein the plastisol layer has a higher durometer hardness rating than the foamed plastisol layer.
 18. The golf club of claim 16 wherein the plastisol layer has a durometer hardness between about 68 to about 72, and the foamed plastisol layer has a durometer hardness between about 15 and about
 20. 19. The golf club of claim 16 wherein the plastisol layer has a durometer hardness of about 70, and the foamed plastisol has a durometer hardness of about
 20. 20. The golf club of claim 16 wherein the plastisol layer is between about 0.03 inch and about 0.06 inch thick and extends about 0.5 inches down from a butt end of the shaft.
 21. The golf club of claim 14 wherein the plastisol grip has a diameter between about 0.9 inch and about 1.1 inches.
 22. The golf club of claim 14 wherein the plastisol grip has a diameter about 1.0 inch.
 23. A grip for a golf club, the grip comprising: a tubular member sized to be fitted over an upper end of a shaft of the golf club, the tubular member being greater than 11 inches and made of a suspension resin containing polyvinyl chloride.
 24. The grip of claim 23 wherein the polyvinyl chloride is suspended in plasticizer.
 25. The grip of claim 23 wherein the suspension resin also contains a foaming agent.
 26. The grip of claim 23 wherein the suspension resin also contains a blowing agent.
 27. A golf club comprising: a shaft; a head mounted on a lower end of the shaft; and a grip mounted on an upper end of the shaft and having a durometer hardness of about
 20. 28. The golf club of claim 27 wherein the grip has a circular cross section and is greater than 11 inches.
 29. The golf club of claim 27 wherein the grip is formed from plastisol.
 30. The golf club of claim 29 wherein the grip is also formed from foamed plastisol. 31., A grip for a golf club having a uniform outer diameter of about 1 inch and having a length of about 19 inches.
 32. A method of making a grip for a golf putter, the method comprising: forming a first flexible layer on a mold rod; forming a second flexible layer over the first flexible layer that defines the length of the grip; and curing the first flexible layer and the second flexible layer.
 33. The method of claim 32 wherein the first flexible layer is plastisol and the second flexible layer is foamable plastisol.
 34. The method of claim 33 and further comprising: preheating the mold rod about 12 minutes at about 415° F. before forming the first plastisol layer.
 35. The method of claim 33 wherein the plastisol and the foamable plastisol are cured between about 9-10 minutes at about 415° F.
 36. The method of claim 32 wherein the first flexible layer has a durometer hardness between about 68 and 72, and the second flexible layer has a durometer hardness between about 15 and
 25. 37. The method of claim 32 wherein the first flexible layer has a durometer hardness of about 70, and the second flexible layer has a durometer hardness of about
 20. 38. The method of claim 32 wherein the mold rod has a diameter similar to a shaft of the golf putter.
 39. The method of claim 32 and further comprising: removing the grip from the mold rod using air pressure; and positioning the grip on a shaft of the golf putter using air pressure.
 40. A method of making a grip for a mid-length golf putter, the method comprising: dipping a mold rod into plastisol; dipping the mold rod coated with the plastisol into foamable plastisol; and baking the plastisol and the foamable plastisol while on the mold rod to form the grip.
 41. The method of claim 40 wherein the plastisol has a higher durometer hardness rating than the foamable plastisol.
 42. The method of claim 40 wherein the mold rod is made of aluminum.
 43. The method of claim 40 wherein the mold rod is made of stainless steel.
 44. The method of claim 40 wherein dipping the mold rod into the plastisol for a dwell-time of between about 10 seconds to 15 seconds.
 45. The method of claim 40 wherein dipping the mold rod coated with the plastisol into the foamable plastisol has a dwell-time of approximately 2.5 minutes.
 46. The method of claim 40 wherein the mold rod is dipped about 0.5 inch into the plastisol.
 47. The method of claim 40 wherein the mold rod coated with the plastisol is dipped about 19 inches into the foamable plastisol.
 48. The method of claim 40 wherein the foamable plastisol contains a foaming agent that foams when baked.
 49. The method of claim 48 wherein the plastisol has a durometer hardness rating greater than the foamable plastisol. 